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. 2025 Oct 24;7(6):fcaf416. doi: 10.1093/braincomms/fcaf416

Figure 4.

Factors contributing to pre- or postsurgical hypertrophy of the contralateral hippocampus in the main cohort were 1.) longer disease duration (trend presurgically, p=0.09 and significant postsurgically), 2.) left-sided lateralisation of the epileptic focus, 3.) presence of ipsilateral hippocampal sclerosis, and 4.) a smaller volume of the ipsilateral hippocampus. On the other hand, presurgical focal to bilateral tonic clonic seizures (FBTCS) were associated with less progressive hypertrophy of the contralateral hippocampus before and after surgery and ongoing seizures after epilepsy surgery were associated with progressive atrophy of the contralateral hippocampal head. There was no association with 1.) age at epilepsy onset, 2.) presurgical seizure frequency, 3.) number of antiseizure medications (ASMs) at surgery, and 4.) the size of the postsurgical hippocampal remnant.

Longitudinal changes of contralateral hippocampal morphology and their association with clinical variables. We correlated the subregional longitudinal changes in contralateral hippocampal morphology before and after epilepsy surgery with clinical variables. We assessed the association with younger age at epilepsy onset (A), longer epilepsy duration (B), left lateralisation of the epileptic focus (C), sclerosis of the ipsilateral hippocampus (D), smaller volume of the ipsilateral hippocampus (E), presurgical seizure frequency (F), presurgical focal to bilateral tonic clonic seizures (FBTCS, G), number of antiseizure medications at surgery (H), ongoing seizures after epilepsy surgery (I) and the size of the hippocampal remnant (J). Blue clusters indicate significantly less progressive hypertrophy, red colours indicate significantly more progressive hypertrophy. We used linear mixed effects models in 23 presurgical and 54 postsurgical TLE patients. Significant P values were thresholded to P < 0.05 corrected for multiple comparisons using familywise error (FWE) correction by random field theory. The contralateral hippocampi are visualized from a superior and an inferior perspective. An approximation of major hippocampal subregional boundaries is overlaid on hippocampal surfaces. CA, cornu ammonis; DG, dentate gyrus; FWE, familywise error; Sub, subiculum.